A basic part of any highway construction project is ground preparation and transportation of earth from one area to another by means of loading, hauling, unloading, leveling, and finally, compacting. Given the massive quantities of earth that must be moved and prepared in some projects, the cost of earthwork including equipment, energy, and labor, contributes significantly to overall project cost. There is therefore a need for improved earth grading and compacting equipment to reduce the cost of roadway preparation. In particular, there is a need for an improved grader and compactor that will allow effective leveling and compaction in fewer passes using basic vehicles rather than specifically dedicated graders and compactors.
It has been standard practice to utilize a dozer or blade to level and smooth new fill. This step typically has been followed by a separate step wherein an operator travels back and forth over the fill area with a compactor such as a sheepsfoot roller. This process enlisted two separate units and two operators, required the replacement of attachments, or required dedicated dozers or graders. Depending on the equipment used, these processes have involved highly paid skilled labor, such as dozer operators rather than tractor operators. Finally, this process resulted in additional time investment due to the increased number of passes caused by the separation of compaction and grading.
U.S. patents directed towards leveling or compacting earth include U.S. Pat. Nos. 2,721,405, 2,891,335, 3,183,804, 3,891,342, 3,924,689, 4,023,288, 4,269,535, 4,490,070, 4,610,567 and 4,911,248. Although these patents disclose various earth leveling or compacting equipment, many relate to ditch filling or compacting devices not proper for application in the large scale earthwork of roadway preparation. Further, many relate to self-propelled machines wherein rollers are positioned rearwardly of drive wheels that serve to disturb leveled fill or wherein rollers are mounted to selectively carry a portion of the vehicle weight. These devices, therefore, are not simple designs for attachment to standard tractors or other standard towing vehicles operable by workers of general rather than specialized skill.
The present invention is a hydraulically controlled leveling blade in a frame or housing with a compacting roller including but not limited to generally cylindrical, angular, sheepsfoot or pad foot rollers pivotally attached behind the blade which makes it possible to level earth and newly placed fill and compact it in one pass. With the blade adjustably attached directly ahead of the roller, the compacting becomes more efficient and often times fewer passes are necessary to reach the desired density. The placement of the roller behind the blade without intervening tracks, wheels, or other ground engaging surfaces permits efficient roller-compacting because the graded earth does not place upon the roller a requirement that the roller perform the role of filling voids and leveling areas of high fill.